1. Field of the Invention
The invention relates to a disc reproducing apparatus for reproducing an optical disc such as a CD-ROM and a DVD.
2. Description of the Related Art
In recent years, most general disc reproducing devices, including, e.g., CD-ROM drives, integrated into personal computers, are the horizontal-front loading type. The disc reproducing apparatus is comprised of a main drive body provided with a mechanism for driving and reproducing a disc, such as an optical pickup, a disc motor, and the like (hereinafter referred to as "the mechanical unit"), and a tray mounting the disc, which is capable of being loaded into and unloaded from the driving main body through a front face thereof in a horizontal position.
The mechanical unit has, as a means for driving the disc, a motor and a turntable fixed to a driving shaft of the motor. The turntable has at its upper face a member which is to be engaged with a center hole of the disc to thereby position the disc. When the tray is loaded into the main drive body, the mechanical unit ascends in order to raise the disc from the tray by the turntable, thereby holding the disc between the turntable and a disc-like member which is called a clamp. The disc is driven and data is reproduced from it with the disc being thus held by the turntable and the clamp.
Further, the general disc reproducing device has an eject button for transmitting to a controller an electrical instructing signal for unloading the tray from the main drive body, after reproduction of data on the disc has been finished. When this eject button is operated, the controller controls the mechanical unit to be lowered by the user, thereby releasing the disc held by the turntable and the clamp, which returns the disc to the tray. Thereafter, the tray is unloaded from the main drive body.
As described above, the horizontal-front loading type disc reproducing device has a mechanism for supporting the mechanical unit and for raising and lowering the mechanical unit between a height of holding the disc between the turntable and the clamp, and a height of enabling the disc to be loaded.
The disc reproducing apparatus including the above mechanical unit raising, and lowering mechanism, generally has the problem that the mechanical unit fluctuates in the main drive body due to external vibrations. For example, the mechanical unit has a raising and lowering mechanism constructed in such a way to rotate the mechanical unit with its back side as a center, with a guide shaft disposed on its front side and guided up and down. In this type device, the mechanical unit is supported at one position of its front side by the guide shaft, which possibly causes a phenomenon in which the mechanical unit is fluctuated from side to side with the one point supported by the guide shaft as a center. Such a fluctuation of the mechanical unit can be decreased by adding a member for supporting a front side of the mechanical unit. However, such a supporting member requires a mechanism for interlocking the supporting member with the ascending and descending movement of the mechanical unit in order to prevent the mechanical unit from ascending and descending. The addition of the supporting member having such a structure, complicates assembly, and increases the cost.
Besides, the conventional horizontal-front loading type disc reproducing device controls the motor to stop when detecting the point of time when finishing clumping the disc and the point of time when finishing unloading the tray, respectively. For example, the of completion of clumping the disc can be detected due to the position of the specific member in the raising and lowering of the mechanism, or the like. In addition, completion of unloading the tray can be detected by constructing a switch in such a manner that the switch can be directly operated through a protrusion disposed on the tray, for operating the switch.
As described above, the disc reproducing device requires many switches for directly detecting the movement of various members, and their operating members. An excessive number of switches and their operating members make the whole construction complicated, and increase the cost.
Further, most horizontal-front loading type disc reproducing devices have mechanisms for loading the tray, and a mechanism for forcedly unloading the tray from the main drive body when a mechanical unit moving mechanism has become inoperable due to failure. This tray can be forcedly unloaded by the user moving a movable member for moving the mechanical unit while supporting it. As means for moving the above movable member, an emergency lever is employed, which is integrated into the drive in manufacture. The emergency lever can be rotated when pressed at its one end by a bar-like member such as a wire, which is inserted into the drive by the user. This rotates the above movable member, thereby lowering the mechanical unit to unload the tray a little from the main drive body.
However, such an emergency lever needs a strong pressing force. Thus, because of the strong pressing force, operation of the emergency lever often makes users feel uneasy, and also causes confusion when the bar inserted into the drive, begins to bond etc.
The same problems described above applies to devices for recording data on to the disc.